Chevy Geardrive System - Keeping In Sync

With Milodon's Simple Geardrive

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Chevy Geardrive System - Keeping In Sync

This is Milodon's latest geardrive system. It features a single idler gear that is solidly attached to the back of the cover.

This is the idler gear mounted on the back of the cover. This is a cast cover that has been machined, and the single idler gear is pressed into a cast boss. The bearings used will ensure its strength in extreme-use conditions.

Once the crank has been installed in the motor, you will need to press the gear over the snout of the crank. This is one of the nicer tools made for this job, but any of them will work.

This is how the three gears will come together behind the cover. The cam button is built into the cam gear, which will sit in the recess on the front of the cover. The button will then press against the machined boss and keep the cam from working its way forward.

You want to make sure that you liberally grease the shim bearing that fits behind the cam. This shim bearing will ensure that the back of the cam gear will spin smoothly, without being affected by the boss in the block.

With the shim bearing in place bolt the cam gear onto the cam. Make sure to use a thread locker, such as Loctite, on the cam bolts.

You will need to torque the cam bolts to 35 ft-lb. We used a vise to hold the cam while we did this. If you wrap a clean rag around the bearing journals, you can gently tighten the vise (with soft jaws, of course) enough to hold it for the torque specs.

When the cam is completely lubed, you will need to guide it into the block. It is very important not to let the cam bang around on the inside of the block.

This boss is where the shim bearing will ride. Here you can see the relationship between the block and cam gear.

Here are the two gears lined up. Unlike other methods of cam-driven timing devices, there aren't any dots that need to be lined up. When done correctly, these are about as precise as you can get.

This may look a little hokey; this is how you will set the lash between the three gears. You need to run a strip of newspaper between them. We used a little bit of grease as an adhesive to keep the paper in place.

Sliding the front cover on and keeping the newspaper in place was a little tough, but thanks to George Vrbancic we were able to pull it off. Once you get the cover in place, you will want to put a couple of bolts in it to hold it from coming off.

You will need to pull the center cover to make sure that the newspaper ran between all three gears. If it looks good, install the rest of the front cover bolts and turn over the motor. You will need to do it enough to run the paper across every tooth of every gear.

Once you have set the lash for the gears, you will need to remove the newspaper. This was also a bit challenging; all the newspaper was retrieved though.

Now that the cover is bolted down, you can drill for an oversized dowel. This was very simple; we just used the bushing in the cover as a guide and drilled our hole.

Set the dowel up in place. It will also be lined up by the bushing in the front cover. Use a ball-peen hammer to install these. A few small taps will do.

With every thing else wrapped up you can re-install the center cover. Make sure that it is put on correctly; this is what will press against the cam button. When you are finished with these last few bolts, so is your install.